1. Field of the Invention
The present invention relates to an image processing apparatus for converting by the dither method or the like a monochromatic or color input image signal into an output signal suitable for digital printing and, more particularly, to an image processing apparatus for dividing an input image signal into blocks by a specific image processing method and for performing different processing for each block.
2. Description of the Prior Art
A digital copying machine is known which photoelectrically reads an original image with a line sensor such as a CCD and records an image on recording paper based on the read image signal.
In such a copying machine, in order to allow reproduction of a high-quality image, a high-resolution image reading method is adopted.
When an image is read with a high resolution, line images such as characters can be reproduced clearly. However, when a dot image or stripe image such as a halftone image (e.g., a printed photograph) is read with a high resolution and when a read output is dither-processed for pseudo-halftone reproduction, the reproduced image is subject to image degradation such as occurrence of moire.
If an image is read at a low resolution in order to prevent moire, the edges of the reproduced image are disturbed.